I can post a bunch of links about it but don't know if you have already read and ruled them out as insufficient or not. For example Wikipedia has a good basic coverage of it that is well support and documented.

If you want more scientific info:

FoodSafety.gov/Listeria

CDC.gov/Listeria

Listeria monocytogenes, a food-borne pathogen

Listeria Monocytogenes - is a gram positive, anaerobic, bacteria, a so-called "hardy bacteria" that is capable of tolerating and surviving is high levels of O2 and growth even under extreme temperature rages of both heat and cold.

It was initially considered primarily a veterinary pathogenic bacteria until research over just the past decade established that it could be transmitted to humans and could survive within the food chain as well as in the soil and water.

If I recall correctly, CDC rates it as having a higher morbidity than c. botulinum but a lower mortality rating. Primary symptoms are gastrointestinal with secondary infections of encephalitis and meningitis causing the fatalities. It is considered a severe threat to pregnant women, children, and those with compromised immune symptoms.

Is it more of a concern for refrigerator pickles than for unpickled fresh vegies? If so, is that due to the brine making eaters less likely to notice that the vegies have gone bad? Or are there no noticeable signs even in unpickled produce? If so, how do you know?

No it is more of a concern for fresh vegetables when proper garden hygiene hasn't been practices or the produce hasn't been well washed. With pickles and such we make the mistake of assuming that the vinegar took care of it and the fridge won't let it grow. But research proves that isn't a safe assumption given time. It just takes longer in an acidic, cold environment for it to grow.
Plus the vegetables mostly get cooked before consuming, the fridge pickles don't.

No obvious noticeable signs in the food.

NCHFP research publications show that

1) brined foods held at room temperature (as most fridge pickle recipes begin with) may contain hazardous levels of listeria if consumed prior to 5-7 days of brining and

2) repeated testings over time of brined, even fridge stored pickles may reach a potentially harmful level of listeria growth after 3 weeks.

This is because the pH does not remain stable, it rises as the brine is diluted by the water in the vegetables. So based on all the variables involved USDA/NCHFP withdrew the fridge pickle recommendations.

Hope this helps.

Dave

Thanks, Dave :). I had read the CDC and foodsafety.org sites, but not their links. And dunno why I didn't think to look at wikipedia :).

Which has an interesting comment:

>Studies suggest up to 10% of human gastrointestinal tracts may be colonized by L. monocytogenes.

This review paper, referenced in the wiki article, looks useful:

http://www.sochinf.cl/documentos/infectologia/listeria.pdf

I haven't read much of it yet, but it's where the quote above comes from.

Here in CO, people who had never heard of it learned a lot two years ago when we had a terrible listeria outbreak from canteloupe melons. The grower had not properly washed the melons, using a converted potato washing system, and not cooled them fast enough before shipping to grocery chains. I think there were three dozen deaths, including one miscarriage, and a hundred or so sickened. Mostly elderly or people with compromised immune systems. I think that's where the quote comes in--if a person has a healthy immune system it can fight off a reasonable amount of listeria bacteria. I had never thought about washing melons before (and have been through professional serv-safe courses for manging a church camp kitchen) since you don't eat the rinds, but they said the bacteria was hiding in the rough skins, then transferred from the knife to the inside fruit when cutting through. Now, all my melons get soaked in a bleach solution before cutting.

I do the same with cantaloupe. That reticulated skin collects a lot of bacteria.

Here we've had a number of severe listeria outbreaks, most associated with dairies and cheese producers. Raw milk is particularly problematic.

Carol

I am trying to wrap my head around the idea of not keeping leftovers longer than 2-3 days in the fridge. That would be an enormous change in how I cook. I normally have a big 'cooking day' once a week or so, in which I make several things in large batches. It would be hard to rearrange my life to cook small quantities, more often. Not to mention, difficult to buy ingredients that way.

Nila - you don't need to change how you cook, just how you store. Freeze the leftovers in portions rather than just keeping them in the fridge.

Dave

@Dave: Yeah, I realise that's an option. But less tasty :(.

baloonflower:
"Here in CO, people who had never heard of it learned a lot two years ago when we had a terrible listeria outbreak from canteloupe melons. The grower had not properly washed the melons, using a converted potato washing system, and not cooled them fast enough before shipping to grocery chainsâ¦â¦ they said the bacteria was hiding in the rough skins, then transferred from the knife to the inside fruit when cutting through. Now, all my melons get soaked in a bleach solution before cutting."

readinglady:
âÂÂI do the same with cantaloupe. That reticulated skin collects a lot of bacteriaâ¦..

In the case of this last food born illness outbreak from cantaloupe, itâÂÂs very probable that washing the outside rind would have little affect in preventing ingestion of the bacterium:

"How do pathogens such as listeria get inside fruits and vegetables? A food safety expert counts the ways

....When they are picked, usually in the heat of summer, cantaloupes are often quickly cooled to halt ripening and preserve quality, the Extension educator said.

Cold showers or water baths are used for cooling; these systems recycle the water they use, and it is important that sanitizer be added to the water, at exactly the proper level, to prevent any bacteria present from multiplying in the water. ThatâÂÂs because the cold water can be absorbed into the fruit through the soft stem end as the fruit contracts a bit during cooling, Tocco said.

" (If) you get a little bit of bacteria in there, every 20 minutes it doubles," he saidâ¦.âÂÂ

Short of cooking the cantaloupe, no amount of food prep hygiene can guard against this sort of (internal) contamination.

Here is a link that might be useful: How do pathogens such as listeria get inside fruits and vegetables? A food safety expert counts the ways

âÂÂConsumers couldn't have washed away cantaloupe contamination, experts say

⦠top U.S. food safety experts say there's one actor in this deadly drama that shouldn't be blamed: The consumer.

No amount of washing, scrubbing, bleaching or peeling would have cleaned cantaloupes contaminated by Jensen Farms' packing practices enough to remove listeria bacteria that has sickened at least 123 people and killed 25 in the deadliest outbreak in a quarter-century.

"There's nothing consumers could have done," said Dr. Doug Powell, a professor of food safety at Kansas State University in Manhattan, Kanâ¦..âÂÂ

Here is a link that might be useful: Consumers couldn't have washed away cantaloupe contamination, experts say

Concerning NCHFP publication, âÂÂListeria monocytogenes survival in refrigerator dill picklesâÂÂ, where the researchers, âÂÂImmersed cucumbers into an inoculum of L. monocytogenes for 15 minâÂÂ, the bacterium were almost certainly drawn in through the stem end, and thus were contaminated internally as noted above. Of course this was done intentionally AFTER washing the cucumbers and prior to fermentation, but once drawn in internally (where the bacteria doubles every 20 minutes) no amount of surface washing can make the cucumber clean, and which is also overwhelming to the ferment, as the experiment undoubtedly showed.

Here is a link that might be useful: Listeria monocytogenes survival in refrigerator dill pickles

This post was edited by sidhartha0209 on Thu, Oct 17, 13 at 9:56

Thanks sidharta for clrearing up the issue.

My question is that if only HIGH temperatures in Pressure Canner can kill the listeria, then what happens in our daily normal eating RAW and cooking fruits and vegetables ?

So the real issue is whether or not the bacterium exists in what we consume. If it does then we have to cook everything in Pressure cooker at 240F. ???

Then as Nila Jones quoted:

" ">Studies suggest up to 10% of human gastrointestinal tracts may be colonized by L. monocytogenes.So this bacterium is not really that foreign and rare to us.

My question is that if only HIGH temperatures in Pressure Canner can kill the listeria,

158F kills Listeria bacteria, It doesn't require a pressure cooker.

...then what happens in our daily normal eating RAW and cooking fruits and vegetables ?

That's not the real question, you got it here:

So the real issue is whether or not the bacterium exists in what we consume.

For the home gardener growing their own vegetables and practicing sound hygiene from garden to kitchen to food prep stage I'd put the realistic risk assessment as being almost nonexistent.

This last outbreak from cantaloupe was particularly bad though:

"... The bacteria clearly contaminated a huge proportion of the more than 310,000 cases of cantaloupe -- between 1.5 million and 4.5 million fruit -- that were recalled by Jensen Farms in mid-September, said Powell.

"Given that 25 people are dead, this was a massive contamination to have that impact," he said...."

Something very unnatural on a huge scale occurred to bring this about; something far more than just dirty hands on a migrant worker.

158F kills Listeria bacteria, It doesn't require a pressure cooker.
(sidharta)
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But thne:
>>>""Listeria Monocytogenes - is a gram positive, anaerobic, bacteria, a so-called "hardy bacteria" that is capable of tolerating and surviving is high levels of O2 and growth even under extreme temperature rages of both heat and cold. (Dave)

"....EXTREM TEMPERATURE ...." ???
what is EXTREME temperature ? Lets iron this out:

This post was edited by seysonn on Thu, Oct 17, 13 at 13:52

Here's the facts, seysonn:

Listeria grows in conditions ranging from 37-104 degrees F and in conditions ranging from 4.4-9.6 pH (Milillo et al. 2012).
Research (which is still ongoing) suggests that Listeria can survive 160 degrees F if there is a large concentration of the bacteria (Mazzotta and Gombas 2001).

I happened to meet one of the Food Science professors from the University of Florida while visiting Gainesville (a chance meeting a couple of years ago at the home of a friend of my dad, but us Food Science geeks love to talk bacteria) - Florida and other agribusiness states are VERY concerned about food-borne pathogens. It is NOT taken lightly at the research level.

Talk to one sometime. Gives you a different perspective and I certainly learned a lot.

Good info Malna.
I don't think that 160F is an EXTREME temperature. So listeria can be easily destroyed just by simple boiling and cooking.

I agree that the agribusiness should take it seriously, because they are dealing with tens of thousands of lives. But as Sidharta pointed out the risk of Listeria infection for home gardener is almost nonexisting.

" But as Sidharta pointed out the risk of Listeria infection for home gardener is almost nonexisting.

Actually it's VIRTUALLY nonexistent for the home gardener practicing sound hygiene from garden to kitchen to table. However, the inner clique/circle of germophobes on this forum ensconced in sterilization technique will not accept that, they desperately desire an image to vent their fear/frustrations towards, and this imaginary over exaggerated threat of listeria gives them just that. An image.

This post was edited by sidhartha0209 on Thu, Oct 17, 13 at 20:07

If following and teaching the USDA Guidelines for Home Food Preservation makes me a germaphobe then fine, I am a proud germaphobe and in good company.

I take comfort from the fact that I have actual scientific research and laboratory testing supporting my position rather than just personal opinion.

Dave

So what is your position digdirt? Is the home gardener practicing sound hygiene from garden to kitchen to table in grave danger of Listeria?

[edit to add]

If yes, then puh-leese cite your source for documented cases of Listeria from sound home gardening practices.

This post was edited by sidhartha0209 on Thu, Oct 17, 13 at 21:53

Actually it's (Listeria)VIRTUALLY nonexistent for the home gardener practicing sound hygiene from garden to kitchen to table. However,(sidharta)
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Another scaring thing here is Botulism. I just made a quick search.
According to the link below, in average 145 cases of Botulism reported each year in the US. The percentage wise breaks down is as follows:

15%-- food born (about 22 cases)
65 % --infant botulism
20 % -- wound botulism

And fortunately not every case results in death. Hear is a quote:

"" However, in the past 50 years the proportion of patients with botulism who die has fallen from about 50% to 3-5%""

So then out of 145 case 5 people die ,of which ONE is food related.
I am sure adhering to safety standards has some effects but over all this is MUCH -ADO ABOUT NOTHING.

Here is a link that might be useful: Botulism

This post was edited by seysonn on Thu, Oct 17, 13 at 22:11

Oh, so since it's rarely fatal (due to modern medical care), botulism is "much ado about nothing"? Fine, you do what you want (I hope you don't have children at home eating your low-acid canned goods), it's any consenting adult's perogative. But as for me, I'd rather avoid the risk of paralysis (permanent or temporary, full or partial) or even a full recovery after a long expensive stay in the ICU.

Let's put it this way - if botulism is no big deal, then why are authorities so worried it could be used as a biological weapon? It's because the hospitals would be overwhelmed, without rapid Dx and treatment and sophisticated long-term medical care, it is almost inevitably fatal - you don't recover from it on your own. It's not the flu (and you know how deadly the 1917 Spanish flu was!).

In all our life , efforts, (social and private) we have to have priorities.
What is number one, what is number two ,,,, so fort.
So the hazards of something that has an occurance of 145 cases, in all US, IN ONE YEAR and only less than 15% percent of all that (22 cases per year, OF WHOM JUST ONE DIES in the course of whole year) is food related, this is one of the lowest priority in our society. We should rather concentrate on the bigger picture and don't loose our perspective. Prevent/fight drugs, alcoholism, cancer causing sources , cholestrole, hypertension, altzheimer .. and ,many many others that hundreds of people are dying EVERYDAY from them. Lets us protect our children from drugs, drunk driving, hundreds dying in just one holiday weekend across America, every holiday.
FIRST LET US SET OUR PRIORITIES.

digdirt:
I take comfort from the fact that I have actual scientific research and laboratory testing supporting my position rather than just personal opinion.

Then answer the questions from 'actual scientific research and laboratory testing' posed to you here:

Here is a link that might be useful: Are my fermenting green beans ok?

In my opinion, the "approved" recipes and practices promoted in this forum are excessively conservative. They define "unsafe" as any recipe not proven safe, and confuse "possible" with "probable". In many ways the ultra conservative positions often stated here are doing a service to readers by making them conscience of some of the key rules for home canning, but in other ways they scare people away from this rewarding hobby and discourage recipe variations.

This thread from a few years ago (linked below) gives an interesting and vigorous discussion of various views on this topic. To each his own, but decisions should be made with facts and perspective.

TomNJ/VA

Here is a link that might be useful: Gardenweb discussion on botulism

Thank you for the link to that thread Tom.

IMO, it's gone beyond 'excessively conservative' to gross exaggeration and fabrication of the facts on the topic of Listeria and fermented vegetables.

Very refreshing reading. The same info that I searched and provided a link(Few posts above).
The bottom line risk reward ratio is slim. As reported just 22 cases of food related Botulism is reported in the course of full year of which the fatality rate is 3 to 5%. That is roughly ONE death. per year in all US.

The proponents of USDA regulations agree(the research) that the most Botulism possibly infected vegetables are like corn, beans, garlic. Don.t we eat tons of them every day without going into great length of trying to disinfect them and worrying about Botulism ? We don't have and need any NCFHP and USDA and BLUE BOOK guidelines for this and we are doing just fine.

We need to get our priorities straight . Lets concentrate on number 1,2,3, .. 100 killers. Botulism is not one of them.

Don.t we eat tons of them every day without going into great length of trying to disinfect them and worrying about Botulism ?

Are you referring to fresh vegetables? Botulism toxin only becomes as issue in an anaerobic environment so fresh or frozen vegetables are never a problem and canned ones are only a problem if the vegetables are inadequately processed and/or the vegetables are inadequately cooked at time of service.

The current low rate of food-related botulism is largely due to standardized canning practices of low-acid foods and stringent efforts of groups like Alaska public health. (There has historically been a high rate of botulism in native populations there but training in early identification and improved treatment have radically reduced the incidence.)

Carol

Are you referring to fresh vegetables? Botulism toxin only becomes as issue in an anaerobic environment so fresh or frozen vegetables are never a problem
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OK
We are talking about what happens after we eat those vegetables that are already infected with Botulism bacteria? Then the bacteria go into our digestive system where there is no air. What happens there ?

The bacteria and the spores do not cause disease. It is the toxin released as the bacteria grows in a hospitable environment (low acid or pH greater than 4.6, anaerobic, high moisture environment with temperatures ranging from 38ðF to 110ðF - in other words, inside a canning jar that is not acidic enough). You have to ingest the toxin itself in order to become ill.

Your digestive system is acidic. As you eat, your stomach releases hydrochloric acid to aid digestion and the pH can drop to as low as 1.2. Normal is 3-4. Botulism spores cannot grow and produce the toxin in an acidic environment.

The highest rate of soil-borne botulism in the U.S. is west of the Rockies. So if fresh vegetables were an issue, there'd be a lot of us sick (or dead).

I know you mentioned prioritizing health and life-quality issues according to their severity and statistical frequency, but I don't see botulism as falling into the same categories.

Many social issues (i.e. carbon in the atmosphere) are politically freighted, complicated and expensive to address. Botulism is none of those things. In the food world with appropriate processing or handling strategies it needn't be an issue at all.

I encourage you to read about botulism itself, the nature of the spores, the many strains, how it's best avoided because that will alleviate many of your concerns. It does no good to understand the statistics if you don't understand the phenomenon.

Carol